During a vehicle impact, occupants may move in a direction influenced by the momentum of a vehicle. Some vehicle impacts, e.g., side impact, frontal offset impacts, far side oblique impacts, near side oblique impacts, etc., may cause the occupants to move at an angle towards vehicle components, e.g., toward an A-pillar, hinge pillar, door, etc. In this situation, the movement of the occupant may result in an increase in brain injury criteria (BrIC), which is a cumulative measurement of rotation of the head of the occupant. A formula for BrIC is standardized by the National Highway Traffic Safety Administration (NHTSA).
During the impact, the head of the occupant may be forced into the airbag to a peak impact position. After the head of the occupant reaches the peak impact position, the head of the occupant may rebound away from the peak impact position, i.e., away from the airbag. BrIC may not increase during the rebound while the head of the occupant remains in contact with the airbag. Following separation of the head of the occupant from the airbag, BrIC may increase as the occupant impacts vehicle components.